import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    var a = 10;
    var b = 20;
    var c;
    return MaterialApp(
      title: 'dart',
      home: Scaffold(
        appBar: AppBar(
          title: Text('dart'),
        ),
        body: Center(
          child: Container(
            child: RaisedButton(
              child: Text('这是准备学习dart的页面'),
              onPressed: () => {
                c = a + b,
                print('打印的在debug模式下的调试控制台$c'),
              },
            ),
          ),
        ),
      ),
    );
  }
}
